Imaging systems are used, for example, in the printing and publishing industry to print magazines, books, etc. Conventional systems include an imager which uses a laser to sensitize (expose) a photo-sensitive photographic media, e.g. conventional photographic film, in a pattern corresponding to the image desired to be printed. Sensitized film is then developed by subjecting it to a photographic aqueous chemical solution in a photographic processor, which may be mechanically coupled to the imager.
The two-dimensional images on the developed film are then photographically transferred to printing plates for use in the printing process. In particular, in contact printing, for example, the developed film is held in contact with the printing plates while the entire assembly is exposed to light.
Because of environmental considerations, however, it is becoming increasingly expensive to properly dispose of the aqueous chemical solution left-over after development of the film. Indeed, it may cost more to dispose of these solutions than it does to purchase them.
In order to solve this problem, a dry silver photographic media, and in particular a dry silver film, which can be photographically developed using heat rather than an aqueous solution, has been produced. In particular, thermally processed silver material (TPSM) is coated in a non-gelatin base to a polyester substrate. The coating is a few microns thick. The film is then exposed to the laser beam of an imager, similar to the way silver halide material is exposed. Heating the exposed film allows catalytic action of the exposed silver crystal to migrate to the surrounding silver soap molecules and cause them to produce a high contrast image --not unlike conventional silver halide film images. This process is described in detail in Imaging Processes And Materials, Neblette's Eighth Edition, Van Nostrand Reinhold, 1989, pp. 279-291, which is hereby expressly incorporated by reference herein. When the thermal process is complete, the film is cooled and then can be used to transfer the image to conventional printing plates.
Such dry silver film, however, requires significantly higher amounts of laser light energy for sensitization (i.e., for sensitizing the silver particles) than does conventional photographic film developed through the use of an aqueous solution. Indeed, imagers for such conventional film do not provide laser light of sufficient energy to sensitize dry silver film.
The use of a more powerful laser in a conventional imager, to replace the typical laser, is not practical because the more powerful laser would occupy a significantly larger amount of space and would be considerably more expensive.